Cutting guide with internal distraction

ABSTRACT

A cutting guide for performing a bone osteotomy procedure is disclosed. The cutting guide includes a first arm having a first cutting guide surface formed therein, a second arm having a second cutting guide surface formed therein pivotably connected to the first arm and a distractor operatively connected to the first arm. The cutting guide is adapted to be affixed to the bone such that the first cutting guide surface is open to the second cutting guide surface. The first arm and second arm are rotatable with respect to each other such that manipulation of the distractor creates a force between the first arm and the second arm causing rotation of the first arm and second arm relative to each other. A method for using the cutting guide in a bone osteotomy procedure is also disclosed.

BACKGROUND OF THE INVENTION

High tibial osteotomy (“HTO”) procedures have become well-establishedmeans of treating unicompartmental degenerative arthritis of the knee.This condition occurs due to uneven weight bearing of the femoralcondyles on either of the medial or lateral joint compartments of thetibia. Such uneven weight bearing results from either a varus or valgusdefect in the tibia. A varus or valgus defect occurs when the knee jointshifts either medially (valgus) or laterally (varus) with respect to themechanical axis. It is generally accepted that the preferred locationfor the mechanical axis of the knee is at about 62% of the tibialplateau from medial to lateral. The process for determining the locationof the mechanical axis is known in the art. A varus deformity generallyresults in increased loading on the medial joint compartment, while avalgus defect results in increased loading on the lateral jointcompartment. A high-tibial osteotomy procedure uses one of varioustechniques to bring the knee into proper mechanical alignment bycorrecting a deformity therein, whether varus or valgus.

One existing high-tibial osteotomy procedure is the opening wedge HTO.In this procedure, a single cut is made from, for example, the medialcortex of the tibia across to near the lateral cortex in order tocorrect a varus defect. The cut in an opening wedge HTO procedureextends through almost the entire tibia, leaving only enough bone on thelateral tibia to form a hinge section which serves to keep the tibialplateau connected to the remainder of the bone. The cut is then forcedopen to form a wedge having an angle corresponding to the requiredamount of angular correction. This procedure can also be used to correcta valgus defect, with the cut originating on the lateral tibia,extending through the tibia to near the medial tibia. The necessary cutis typically made using a cutting guide, of which various forms areknown, affixed to the tibia.

Upon completion of the cut, the cutting guide, should one be used in theprocedure, is removed and the bone is typically displaced by insertingtwo plates into the cut and turning a jackscrew. A metal wedge may alsobe used to expand the wedge cut by impacting the wedge into the cut andadvancing it until the desired amount of correction is achieved. Oncethe cut is opened, an appropriately shaped spacer can be inserted intothe cut to support the tibial plateau at the desired angle. The spacercan be made of a known bone-substitute material, an autograft taken fromthe patient's iliac crest or an allograft taken from a donor. The wedgeis then secured in place using hardware typically in the form of boneplates and screws.

An alternative procedure is what is known as a closing-wedge osteotomy.In such a procedure, a wedge of bone is removed from the tibia, closingthe opening left by the removal of the wedge, and securing the bone inits new configuration. The wedge is shaped to correspond to theappropriate amount of angular correction necessary to bring the kneejoint into proper alignment. Generally the wedge is shaped so as to spanalmost the entire medial-lateral width of the tibia, leaving only anarrow “hinge” section of bone on the closed end of the wedge. Once thebone wedge is resected, the opening is forced closed and is typicallyheld in such a position using a staple or other similar device,including bone screws and/or plates. Such procedures are shown in U.S.Pat. No. 5,980,526 to Johnson, et al.; U.S. Pat. No. 6,796,986 toDuffner; U.S. Pat. No. 5,911,724 to Wehrli; U.S. Pat. No. 5,053,039 toHoffman, et al.; U.S. Pat. No. 5,540,695 to Levy, and; U.S. Pat. No.5,601,565 to Huebner.

Various tools have been developed in order to facilitate both theopening and closing wedge osteotomy procedures. Typically, these toolsinclude various cutting guides which are capable of being affixed to thebone and provide a surface which is used to guide a bone saw or otherknown instrument into proper alignment for the desired cut or cuts.Typically, these guides are designed to affix to either the medial orlateral side of the tibia, depending on the type of correction requiredand the procedure used. By taking either a medial or lateral approachfor cutting, the patellar tendon is easily avoided. However, theseapproaches make alignment of cuts more difficult because the mechanicalaxis is not visible from the side of the knee. In the use of the variousinstruments for forming the appropriate cuts for both opening andclosing wedge HTO procedures, the instruments must be removed prior toeither opening or closing the wedge. This adds an additional step whichprolongs the procedure. Furthermore, in the case of opening wedge HTOinstrumentation, the device used to open the wedge must often be removedprior to attempting insertion of a filler implant, should one be used.This is problematic, should further opening of the wedge be necessary,as this would require the device to be re-attached to the tibia.

SUMMARY OF THE INVENTION

The present invention relates to a cutting guide for performing a boneosteotomy procedure. The cutting guide includes a first arm having afirst cutting guide surface formed therein, a second arm having a secondcutting guide surface formed therein pivotably connected to the firstarm and a distractor operatively connected to the first arm. The cuttingguide is adapted to be affixed to the bone such that the first cuttingguide surface is open to the second cutting guide surface. The first armand second arm are rotatable with respect to each other such thatmanipulation of the distractor creates a force between the first arm andthe second arm causing rotation of the first arm and second arm relativeto each other. In a preferred embodiment, the bone is the proximal tibiaand the cutting guide is adapted to be affixed to the anterior portionof the proximal tibia.

In a preferred embodiment, the distractor is a screw that is operativelyengaged with the first arm by insertion within a threaded hole in thefirst arm such that rotation of the screw causes axial motion of thescrew with respect to the first arm in a direction away from the firstcutting guide surface.

In an alternative embodiment, the distractor is a screw, wherein thescrew is operatively engaged with the first arm by passing through anopening in the first arm, and wherein the screw is threadably engagedwith a threaded hole in the second arm. The screw may include a headportion with a shoulder section formed therein so as to face an outsidesurface of the first arm, wherein rotation of the screw causes axialmovement of the screw with respect to the second arm such that theshoulder section contacts the outside surface of the first arm.

The cutting guide of the present invention may also include a firstrounded groove formed in the first cutting guide surface and a secondrounded groove formed in the second cutting guide surface. The first andsecond rounded grooves together form a drill guide extending from ananterior surface of the cutting guide to a posterior surface of thecutting guide.

In one embodiment of the cutting guide, the hinge portion is disposed ona first side of the patellar tendon and the first and second cuttingguide surfaces extend along and contact the proximal tibia on a secondside of the patellar tendon. In this embodiment, the first arm mayinclude a first fixation hole and the second arm may include a secondfixation hole. The first and second fixation holes are preferablyadapted for sliding engagement with respective first and second fixationpins inserted into the second side of the proximal tibia.

In an alternative embodiment of the cutting guide, the first arm and thesecond arm are connected by a flexible hinge portion extendingtherebetween such that the cutting guide has an original shape whereinthat the first cutting guide surface is substantially parallel to thesecond cutting guide surface. Preferably, the first arm, the second arm,and the flexible hinge portion are integrally formed. Furtherpreferably, the hinge portion has an inner surface and an outer surface,each of the inner and outer surfaces forming substantially co-axialcylindrical portions. The radius of the outer cylindrical portion ispreferably greater than the radius of the inner cylindrical portion byan amount forming a thickness of the hinge portion. The thickness of thehinge portion is preferably sufficient to permit flexing whilesubstantially retaining the original shape of the cutting guide.

A further embodiment of the present invention relates to method ofperforming a bone osteotomy procedure. The method includes the step ofaffixing a cutting guide to the bone in a first position. The cuttingguide includes a first arm having a first cutting guide surface formedtherein, a second arm having a second cutting guide surface formedtherein, and a distractor operatively engaged with the first and secondarms. The first arm and second arm are rotatable with respect to eachother and positioned on the bone such that the first cutting guidesurface is open to the second cutting guide surface. The method furtherincludes forming a first cut through a portion of the bone using acutting instrument in connection with the first and second cutting guidesurfaces, and manipulating the distractor so as to cause the first armto rotate relative to the second arm. Preferably, the bone is theproximal tibia, and the step of affixing the cutting guide to the boneincludes affixing the cutting guide to the proximal tibia.

In a further embodiment of the method, the distractor is a screw and isoperatively engaged with the first arm by engaging with a threaded holein the first arm. The step of manipulating the distractor includesrotating the screw so as to cause axial motion of the screw in adirection substantially normal to the first cutting guide surface.

In an alternative embodiment, the distractor is a screw slideablyengaged with an opening in the first arm and threadably engaged with athreaded hole in the second arm. The step of manipulating the distractorincludes rotating the screw so as to cause axial motion of the screwrelative to the second arm. This method may further include forming asecond cut in the proximal tibia at an angle relative to the first cutsuch that the second cut intersects the first cut so as to create awedge of bone. The wedge of bone may then be removed from the proximaltibia so as to form a wedge-shaped opening in the proximal tibia. Thescrew is then rotated so as to cause the first arm and second arm torotate toward each other so as to close the wedge-shaped opening in theproximal tibia. The second cut may be formed using a cutting instrumentin connection with the first and second cutting guide surfaces. The stepof forming the second cut may include detaching the cutting guide fromthe proximal tibia and re-attaching the cutting guide to the proximaltibia in a second position.

As used herein when referring to bones or other parts of the body, theterm “proximal” means close to the heart and the term “distal” meansmore distant from the heart. The term “inferior” means toward the feetand the term “superior” means toward the head. The term “anterior” meanstoward the front part or the face and the term “posterior” means towardthe back of the body. The term “medial” means toward the midline of thebody and the term “lateral” means away from the midline of the body.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood on reading the followingdetailed description of nonlimiting embodiments thereof, and onexamining the accompanying drawings, in which:

FIG. 1 is an isometric view of a cutting guide according to anembodiment of the present invention;

FIG. 2. is an elevation view of the cutting guide of FIG. 1 from ananterior direction;

FIG. 3 is an exploded view of the cutting guide shown in FIGS. 1 and 2affixed to a proximal tibia;

FIG. 4 is an anterior elevation view of the cutting guide shown in FIGS.1 and 2 affixed to a proximal tibia;

FIG. 5 is an anterior elevation view of a proximal tibia having a cutformed therein using the cutting guide shown in FIGS. 1 and 2;

FIG. 6 is an isometric view of an implant used in securing a cut formedduring a procedure utilizing the cutting block according to anembodiment of the present invention;

FIG. 7 is an anterior view of a cut formed in a proximal tibia using acutting block according to an embodiment of the present invention andsecured with an implant shown as shown in FIG. 6.

FIGS. 8-11 are anterior views of a proximal tibia having a cutting guideaffixed thereto during steps of an HTO procedure;

FIG. 12 is an alternative embodiment of a cutting guide for use in abone osteotomy procedure;

FIG. 13 is an exploded view of the guide shown in FIG. 12.

FIG. 14 is an isometric view of a further alternative embodiment of acutting guide for use in a bone osteotomy procedure;

FIG. 15 is a front elevation view of the guide shown in FIG. 14.

DETAILED DESCRIPTION

An exemplary embodiment of a cutting guide 10 according to an embodimentof the present invention is shown in FIG. 1. Generally, cutting guide 10is adapted to be affixed to a bone surface, and, in the particularembodiment shown in FIG. 1, is adapted to be affixed to the anteriorsurface of the proximal portion of a human tibia. Cutting guide 10includes a hinge portion 16 on one end and a guide portion 20 on anotherend.

Hinge portion 16 is adapted to be positioned partially over the patellartendon which is associated with the proximal tibia and to extend towarda first side thereof. Guide portion 20 is adapted to contact a portionof the proximal tibia on a second side of the patellar tendon such thathinge portion 16 is spaced apart from the anterior surface of theproximal tibia at a distance adequate to prevent hinge portion 16 fromcontacting or otherwise interfering with the patellar tendon. By way ofexample, guide 10 is shown and described as being adapted for performingwhat is generally-known as an opening wedge HTO including forming asingle cut through the medial cortex of a patient's left proximal tibia.As shown in FIGS. 1 through 4, guide portions 20 a and 20 b arepreferably shaped so as to extend from the proximal surface M of thetibia toward and partially contacting the medial surface of the tibiaextending substantially toward the posterior cortex of the tibia.Cutting guide slot 24 is preferably included in this portion of cuttingguide 10.

In describing preferred embodiments of the cutting block of the presentinvention, reference will be made to directional nomenclature used indescribing the human body. It is noted that this nomenclature is usedonly for convenience and that it is not intended to be limiting withrespect to the scope or structure of the invention. When referring tospecific directions, the device is understood to be described only withrespect to its orientation and position during an exemplary applicationto the human body.

Guide 10, preferably, includes two portions: a first arm 12 and a secondarm 14. First arm 12 includes a first guide portion 20 a and a firsthinge portion 16 a, and second arm 14 includes a second guide portion 20b and a second hinge portion 16 b. Hinge portions 16 a, 16 b arestructured to allow first arm and second arm 14 to rotate with respectto each other. Preferably, this is achieved by including matching holes18 a, 18 b in first and second hinge portions 16 a, 16 b, respectively.In the example of cutting guide 10 shown in FIG. 1, first hinge portion16 a is positioned anteriorly of second hinge portion 16 b such thathole 18 a aligns with hole 18 b along the respective longitudinal axesthereof. A hinge pin or drill bit 50 (not show in FIG. 1) is insertedthrough holes 18 a, 18 b to secure the relative position of first andsecond arms 12, 14 in the proximal-distal and medial-lateral directionswhile permitting first arm 12 and second arm 14 to rotate relative toeach other. Preferably, pin 50 is also used as an affixation member inaffixing guide 10 to the proximal tibia by inserting pin 50 into a holethat is formed, preferably by drilling, in the proximal tibia at theappropriate location.

In a preferred embodiment, hinge portions 16 a, 16 b each includemultiple pairs of holes 18 a, 18 b, which allow the user of guide 10 toselect the appropriate pair into which to insert pin 50. This allowsguide 10 to be adapted to better fit the shape and structure of thespecific proximal tibia on which the procedure is carried out,particularly with respect to the location of guide portion 20 and pin50.

Guide portion 20 includes a cutting guide slot 24 formed therein, whichis adapted for use with various forms of cutting instruments used inorthopedic procedures. These cutting instruments include various formsof bone saws, such as oscillating saws, osteotomes and OTIS saws.Cutting guide slot 24 is formed by a first cutting guide surface 26 aformed on first guide portion 20 a and a second cutting guide surface 26b formed on second guide portion 20 b. First and second arms 12, 14 canbe rotated into a position such that first and second cutting guidesurfaces 26 a, 26 b are substantially parallel to each other and arespaced apart from each other at a distance sufficient to accept acutting instrument therebetween, allowing the cutting instrument toslide freely within cutting guide slot 24 while providing a fit that issufficient to accurately guide the cutting instrument along a pathdefined by cutting guide slot 24.

To allow for more accurate spacing between first cutting guide surface26 a and second cutting guide surface 26 b during use and placement ofcutting guide 10, first arm 12 and second arm 14 can, respectively,include a first blocking surface 28 a and a second blocking surface 28b. As shown in FIG. 3, blocking surfaces 28 a, 28 b are substantiallyparallel to their respective cutting guide surfaces 26 a, 26 b and arespaced apart therefrom. Preferably, blocking surfaces 28 a, 28 b arespaced apart from their respective cutting guide surfaces 26 a, 26 b ata distance that is approximately equal to half of the desired distancebetween first and second cutting guide surfaces 26 a, 26 b.Alternatively, only one blocking surface may be included on either firstarm 12 or second arm 14 at a sufficient height to ensure proper spacingbetween cutting guide surfaces 26 a, 26 b.

First and second arms 12, 14 can further include vertical walls 30 a, 30b, respectively, positioned between the respective cutting guidesurfaces 26 a, 26 b and blocking surfaces 28 a, 28 b. Vertical walls 30a, 30 b act in conjunction with cutting guide surfaces 26 a, 26 b toform a terminal end 31 for cutting guide slot 24 that can further act toproperly guide a cutting instrument during use with cutting guide 10.

Cutting guide 10 further includes a distraction mechanism formedintegrally therewith. The distraction mechanism is used in manipulatingthe rotational relationship between first arm 12 and second arm 14. Inthe embodiment shown in FIGS. 1-3, the distraction mechanism includes athreaded hole 36 formed in first arm 12 into which a screw 34 isoperatively engaged. When screw 34 is advanced into hole 36, it contactsa portion of second arm 14, such as blocking surface 28 b, causing aforce to be exerted thereon, which acts to cause first arm 12 and secondarm 14 to rotate with respect to each other such that first and secondcutting guide surfaces 26 a, 26 b move away from each other. In analternative embodiment, the distraction mechanism may include a throughhole formed in first arm 12, a threaded hole formed in second arm 14 anda screw. The screw passes through the appropriately-sized through holeand engages the treaded hole. The head of the screw is positioned on theoutside surface of first arm 12 such that, when screw 34 is advancedinto the threaded hole, the inside surface of the screw head is drawninto contact with the first arm. This contact causes a force to beexerted between first and second arms 12, 14 causing rotational movementtherebetween such that first and second cutting guide surfaces 26 a, 26b move toward one another.

Cutting guide 10 is formed of a material sufficient to give cuttingguide 10 an appropriate rigidity to accurately guide a cuttinginstrument for formation of the cuts necessary for the HTO procedure.Additionally, cutting guide 10 may be made from a material that allowsfor multiple uses, which includes the ability to be repeatedly subjectedto the various sterilization procedures used in the art. Acceptablematerials for cutting guide 10 include, but are not limited to, surgicalsteel, titanium or other similar materials.

A further embodiment of the present invention includes a method forperforming an opening-wedge high-tibial osteotomy procedure on a patientusing guide 10 shown in FIGS. 1-3. In performing this procedure, accessis gained to the proximal tibia through an appropriately-sized,retracted incision. First drill hole 80 is formed starting at theanterior portion of the proximal tibia and passing through the posteriorcortex thereof. First drill hole 80 should be positioned at the desiredapex of the wedge that is to be formed in the surgery. Once first drillhole 80 is formed, the drill bit 50 is removed from the drill and isleft in first drill hole 80. Second arm 14 is then assembled onto drillbit 50 by sliding drill bit 50 through hole 18 b or anappropriately-selected one of a set of holes. Generally, one of a set ofholes 18 b is selected such that guide portion 20 contacts the proximaltibia along the back edge 21 a thereof, while providing appropriateanterior spacing of hinge portion 16 relative to the patellar tendon,such that hinge portion 16 does not interfere with the patellar tendon.The proper angular alignment is selected for second arm 14, which issuch that second cutting guide surface 26 b is aligned with the selectedposition for the cut to be formed in connection with the procedure.Guide hole 22 b is then used as a guide for forming second drill hole 84in the proximal tibia. An affixation member in the form of a first pin54 is then inserted into second drill hole 84 to secure the position ofsecond arm 14 relative to the proximal tibia.

First arm 12 is then affixed to the proximal tibia by first engaginghole 18 a with drill bit 50 and sliding first arm 12 along drill bit 50until the back edge 21 a of first arm 12 contacts the proximal tibia.First arm is then aligned such that first blocking surface 28 a contactssecond blocking surface 28 b. Third drill hole 83 is then formed in theproximal tibia using first hole 22 a. An affixation member in the formof a second pin 52 is then inserted through hole 22 a and into thirddrill hole 83. In a preferred embodiment of guide 10, holes 22 a areformed substantially parallel to each other and are further formed at anangle relative to holes 18 a, 18 b such that when pins are inserted intoguide 10 so as to affix guide 10 to the proximal tibia, the angulararrangement of pins 52, 54 helps to retain guide in its position.

Once first and second arms 12, 14 of guide 10 are affixed to theproximal tibia in the proper position, a cutting instrument, asdescribed above, is slid into the cutting guide slot 24, which is formedby first and second cutting guide surfaces 26 a, 26 b, in order to forman appropriate cut 82 in the proximal tibia. Preferably, the cuttinginstrument is positioned in a generally anterior-posterior directionsuch that a side edge thereof contacts the terminal end 31 of cuttingguide slot 24. Terminal end 31 is preferably of a sufficient length inthe anterior-posterior direction to provide stability for the cuttinginstrument along the plane formed by terminal end 31. Preferably, thecut 82 is initiated by engaging the cutting instrument with cuttingguide slot 24 such that an edge of the cutting instrument abuts terminalend 31 so as to be slidably engaged therewith, thereby assisting theuser in making cut 82 such that it is oriented substantially in theanterior-posterior direction through the anterior cortex of the tibiawithout interfering with the patellar tendon. The cutting instrument isthen continued to be moved substantially in the anterior-posteriordirection until cut 82 penetrates the posterior cortex of the tibia.

Once cut 82 has been started, the user of guide 10 may then proceed tocomplete cut 82 by freely moving the cutting instrument within cuttingguide slot 24. Such movement may include rotating the cutting instrumentalong the plane formed by cutting guide slot 24 so as to extend cut 82behind the patellar tendon of the patient and through the entireproximal tibia along the proscribed cutting path. The placement of drillbit 50 at the hinge portion between first and second arms 12, 14effectively blocks cutting guide therealong, forming the end of the cutat the desired location and providing a widened, rounded apex of the cutthat reduces the stress concentration that may result from subsequentexpansion of the cut.

Having completed the formation of cut 82 in the proximal tibia, the userof guide 10 then removes the cutting instrument from cutting guide slot24 and inserts screw 34 into threaded hole 36. Screw 34 is then turnedso as to advance it into threaded hole 36 such that the tip of screw 34contacts a portion of second arm 14 and creates a force between firstarm 12 and second arm 14, which is then transferred, via pins 52, 54into the proximal tibia at a location above and below cut 82. Thecontinued advancement of screw causes cut 82 to open by forcing apartthe portions of proximal tibia that are separated by cut 82. Thisrequires the portion of proximal tibia that is left connecting the twoseparate portions to flex to accommodate the opening cut 82. The screwis turned, thereby opening cut 82 into the shape of a wedge having theappropriate angle for correction of the defect.

The bone is then secured in the position achieved through advancement ofscrew. This can be done by using known devices including staples orspacers. A preferred embodiment of guide 10 includes a drill guide 38formed between first and second cutting guide surfaces 26 a, 26 b suchthat a drill can be guided thereby into the proximal tibia when guide 10is secured to the proximal tibia in the closed position. The drill usedin conjunction with drill guide 38 is sized so that portions of thedrill hole form semi-cylindrical channels 85 a, 85 b on both sides ofcut 82. In a procedure using such guide, a drill hole is formed using adrill in conjunction with drill guide 38, preferably prior to formingthe cut in the proximal tibial. The wedge can then be secured inposition using a spacer 60 shown in FIGS. 6 and 7. Spacer 60 includessemi-cylindrical projections 62, 64 extending from opposite sidesthereof which are adapted to mate with the corresponding channels 85 a,85 b formed in the proximal tibia and a flange 66 that extends betweenthe inner surfaces of the wedge. The thickness T of flange 66 isselected to maintain the appropriate angle for the wedge formed duringthe procedure. Flange 66 may be angled so as to substantially match thedesired angle for the wedge.

The mating of projections 62, 64 with channels 85 a, 85 b helps toprovide stability for the spacer and the joint overall during thehealing process. In particular, it helps to add to the torsionalstability of the tibial plateau relative to the remainder of the bone toaid in insertion of spacer 60. Screw 34 may be turned so as to expandthe size of the wedge beyond the desired angle for correction of thedefect. Once spacer 60 is in place, the guide is then removed from thebone, and the wound is closed.

An alternative method for performing an HTO procedure can be completedusing a variation of the guide shown in FIGS. 1-5. Guide 110, as shownin FIGS. 8-11 is similar in structure to guide 10, except that screw 134passes through a through hole 136 in first arm 112 and engages athreaded hole 137 in second arm 114. In this embodiment, screw 134 isused to create a force between first arm and second arm 112, 114 thatcauses arms 112, 114 to be drawn toward one another. This isaccomplished by turning screw 134 such that the bottom edge of the screwhead 135 is brought in to contact with the outside surface 113 of firstarm 112. The screw is continued to be turned, causing the opposingforces of the screw head on the first arm and the screw threads on thesecond arm to draw the arms 112, 114 together. Other mechanisms may beused to affect the necessary force between first and second arms 112,114, including levers, ratchet mechanisms and the like.

The embodiment of guide 110 shown in FIGS. 8-11 is useful in performinga closing wedge HTO procedure, in which two appropriately shaped andlocated cuts 182, 190 are formed in the proximal tibia in order to forma wedge of bone 194 that is removed from the tibia, thereby creating awedge-shaped opening 192 therein. The wedge-shaped opening 192 is thendrawn closed and secured in order to achieve the desired amount ofangular correction for the joint. In performing this procedure, guide110 is used to form both cuts 182, 190 and to draw the wedge-shapedopening 192 closed.

Guide 110 is used to form first cut 182 by first affixing guide 110 inthe appropriate location therefor. This is done by first forming a firsthole 180 in the proximal tibia at the desired location for the apex ofthe wedge 192 that is to be formed. The drill bit 150 used to form thehole 180 may be left in place after formation of hole 180 or may bereplaced with a similarly-sized pin. Second arm 114 is then placed onthe proximal tibia by engaging an appropriate one of hinge holes 118 bwith drill bit 150. Second arm 114 is then aligned on the proximal tibiasuch that second cutting guide surface 126 b is aligned with the desiredlocation for the first cut. A second hole 184 is then drilled in theproximal tibia using hole 122 b into which first pin 152 is inserted inorder to hold second arm 114 in place. First arm 112 is then affixed tothe proximal tibia by aligning one of holes 118 a that corresponds tothe selected one of holes 118 b with drill bit 150 and engaging it withhole 118 a such that the posterior edge of first arm 112 contacts aportion of the proximal tibia. A third drill hole 183 is then formed inthe proximal tibia using hole 122 a into which pin 154 is inserted.First cut 182 is then formed using a cutting instrument in connectionwith cutting guide slot 124 in a manner similar to that which isdiscussed above.

After formation of first cut 182, pin 152 is removed from the proximaltibia and from hole 122 b. Screw 134 is then turned so as to withdrawscrew 134 from second arm 114, thereby allowing second arm 114 to rotateaway from first arm 112 and causing second cutting guide surface 126 bto form an angle relative to first cutting guide surface 126 a. Screw134 is turned until second cutting guide surface 126 b is substantiallyaligned with the desired position for second cut 190. When thisalignment is achieved, second arm 114 is, again, secured to the proximaltibia by forming a fourth hole 186 using hole 122 b and inserting pin152 through hole 122 b and into fourth hole 186. Pin 154 is then removedfrom hole 122 a in first arm 112 thereby making first arm free to rotateabout drill bit 150. First arm 112 is then rotated, either freely or byturning screw 150, such that first blocking surface 28 a contacts secondblocking surface 28 b. First arm is then secured in place by formingfifth drill hole 188 in the proximal tibia and inserting pin 154 throughhole 122 a and into fifth drill hole 188. Second cut 190 is then formedin the proximal tibia using a cutting instrument in connection withcutting guide slot 124, thereby forming a removable wedge 194 in theproximal tibia.

Pin 154 is then removed from the proximal tibia and from hole 122 a.First arm is then rotated such that hole is re-aligned with the secondhole 183 formed in the proximal tibia and pin 154 is inserted throughhole 22 a and into second hole 183. Wedge 194 is then removed from theproximal tibia, forming wedge-shaped opening 192 in the proximal tibia.Opening 192 is then drawn closed using guide 110 by turning screw 134 inthe manner described above in order to rotate first and second arms 112,114 together. The attachment of guide 110 to the proximal tibia willcause opening 192 to close by rotating the tibial plateau with respectto the remainder of the bone. When the wedge is being closed, it may benecessary to remove drill bit 150 from the bone, leaving drill bit 150engaged with cutting guide 110 or to replace drill bit 150 with a pin ofa smaller diameter.

It is to be understood that the particular order of steps describedherein is merely exemplary and that the order of the cuts formed may bevaried in such a procedure and that the affixation of the variouscomponents of guide 110 and the manipulation thereof, as describedabove, may be altered to accommodate such variations.

An alternative embodiment guide 210 is shown in FIGS. 12 and 13. Guide210 includes a first arm 212 and a second arm 214 which are connectedusing a pin 250 that is inserted through hole 218 a, included in firstarm 212, and hole 218 b, included in second arm 214. Preferably, hole218 a and hole 218 b are located in respective hinge sections 216 a, 216b of first and second arms 212, 214 which interdigitate when first andsecond arms 212, 214 are assembled together. First and second arms 212,214 each include a cutout portion 221 a, 221 b, which are positioned soas to substantially align with each other when guide 210 is assembled,and which allow cutting guide 210 to be positioned so as to straddle thepatellar tendon of the patient as shown in FIG. 12. This straddling ofthe patellar tendon allows the back edge sections 223 a, 223 b of theassembled guide 210 to contact the proximal tibia on both sides of thepatellar tendon.

Both first arm 212 and second arm 214 include a respective cutting guidesurface 226 a, 226 b which can be aligned substantially parallel to oneanother and spaced apart from one another at a predetermined distance toform a cutting guide slot 224, which is preferably sized so as toprovide support for a cutting instrument used in connection therewith.First arm 212 includes a screw hole 236 into which a screw 234 may beinserted. Screw hole 236 is positioned such that when screw 234 isadvanced thereinto, it contacts cutting guide surface 226 b formed inSecond arm 214 and creates a force between first arm 212 and second arm214 that causes first and second arms 212, 214 to rotate away from eachother.

An alternative embodiment of guide 310 is shown in FIGS. 14 and 15. Thisembodiment is similar in structure to guide 210, shown in FIGS. 12 and13, but is made from a unitary piece of material, preferably plastic.First arm 312 and second arm 314 are connected by hinge portion 316,which is designed to be flexible so as to accommodate the rotationbetween first and second arms. The shape and thickness of the materialin hinge portion 316 should be such that hinge portion 316 is moreflexible than first and second arms 312, 314, and should be such thatmovement of first and second arms 312, 314 relative to each other can beachieved without causing breakage of guide 310 or without requiring ahigh level of force to be exerted on screw 334, which could causebinding of screw 334 or difficulty for the user of the device. Ingeneral the thickness of the material from which guide 310 is madeshould be less in hinge portion 316 than in first and second arms. Hole318 is included in hinge portion 316 and is adapted to receive a drillbit 350 or pin therein for affixing guide 310 to the proximal tibia.Additionally, the position of hole 318 within hinge portion 316 servesto eliminate stress concentrations in hinge portion 316 during flexingthereof. Holes 322 a, 322 b are included in first and second arms 312,314, respectively, and are adapted for receiving pins (not shown)therein for affixing guide 310 to the proximal tibia.

Methods for performing an opening wedge osteotomy procedure using eitherguide 210 or guide 310 are similar, the primary difference being thatwhen using guide 210, first and second arms 212, 214 must be assembledtogether. Furthermore, the method by which both opening and closingwedge HTO procedures are conducted using guides 210 and 310 are similarto those discussed with respect to the use of guides 10 and 110,including the particular modifications that may be made to guides 210and 310 in order to perform a closing wedge HTO procedure. The primarydifference in the methods is in the formation of the cuts that iscarried out in the procedure. Unlike guides 10 and 110, guides 210 and310 do not extend along either the medial or lateral side of theproximal tibia. Accordingly, in order to extend the cuts in the proximaltibia behind the patellar tendon, a different procedure is used.Specifically, the cut is started, preferably by driving a cuttinginstrument, such as an oscillating saw, through the proximal tibia in agenerally anterior-posterior direction, without interfering with thepatellar tendon. Next, the patellar tendon is retracted away from theproximal tibia, preferably in the anterior direction, and an L shapedosteotome or other similar instrument such as an OTIS saw is placedbehind and around the patellar tendon and used to finish the cut. Theuse of L-shaped cutting instruments in HTO procedures is discussed inco-pending U.S. patent application Ser. No. 11/480,648, which isincorporated by reference herein.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

The invention claimed is:
 1. A cutting guide for performing a boneosteotomy procedure, comprising: a first arm having a first cuttingguide surface formed therein, the first arm having a first roundedgroove formed therein; a second arm pivotably connected to the firstarm, the second arm having a second cutting guide surface formedtherein, and the second arm having a second rounded groove formedtherein; a distractor operatively engaged with both the first and secondarms; a first affixation member adapted to affix the first arm to abone; and a second affixation member adapted to affix the second arm tothe bone; wherein the cutting guide is adapted to be affixed to the bonewith the first affixation member extending transverse to the first armand into the bone and the second affixation member extending transverseto the second arm and into the bone, such that the first cutting guidesurface faces the second cutting guide surface with the first and secondrounded grooves together defining a substantially circular bore, whereinthe first arm and second arm are rotatable with respect to each other,and wherein actuation of the distractor causes the distractor to apply aforce on the first arm and an oppositely directed force on the secondarm to cause rotation of the first arm and second arm relative to eachother.
 2. The cutting guide of claim 1, wherein the bone is a proximaltibia, and wherein the cutting guide is adapted to be affixed to ananterior portion of the proximal tibia.
 3. The cutting guide of claim 1,wherein the distractor is a screw and is operatively engaged to thefirst arm by insertion within a threaded hole in the first arm such thatrotation of the screw causes axial motion of the screw with respect tothe first arm in a direction away from the first cutting guide surface.4. The cutting guide of claim 1, wherein the distractor is a screw, andwherein the rotation of the screw causes the first arm and the secondarm to rotate toward each other.
 5. The cutting guide of claim 2,wherein the first and second cutting guide surfaces each include aportion thereof which extends in an anterior-posterior direction along aside cortex of the proximal tibia when the cutting guide is affixed tothe proximal tibia.
 6. The cutting guide of claim 2, wherein the firstarm includes a first hinge portion and the second arm includes a secondhinge portion, wherein the first and second hinge portions arepositioned such that the first and second hinge portions are spacedanteriorly from and at least partially overlie a patellar tendonassociated with the proximal tibia when the cutting guide is affixed tothe proximal tibia.
 7. The cutting guide of claim 6, further including ahinge pin, wherein the first hinge portion includes a first hinge holeformed therein and the second hinge portion includes a second hinge holeformed therein, and wherein the hinge pin is adapted to be inserted intothe bone and to slideably engage the first hinge hole and the secondhinge hole.
 8. The cutting guide of claim 7, wherein, when the cuttingguide is affixed to the proximal tibia, the first and second hinge holesare disposed on a first side of the patellar tendon and wherein thefirst and second cutting guide surfaces are disposed at least partiallyon a second side of the patellar tendon.
 9. The cutting guide of claim7, wherein the first hinge hole is one of a first plurality of holesformed in the first hinge portion, and wherein the second hinge hole isone of a second plurality of holes formed in the second hinge portion.10. The cutting guide of claim 7, wherein the first affixation member isa first fixation pin and the second affixation member is a secondfixation pin, and wherein the first arm includes a first fixation holeand wherein the second arm includes a second fixation hole, the firstand second fixation holes being adapted for sliding engagement with therespective first and second fixation pins when inserted into theproximal tibia, the first and second fixation holes each having alongitudinal axis that is angled relative to a longitudinal axis of thefirst hinge hole.
 11. The cutting guide of claim 1, wherein the firstarm includes a first blocking surface and wherein the second armincludes a second blocking surface, the first and second blockingsurfaces being opposed to each other such that the first and second armsare capable of being positioned relative to each other in a firstposition such that the first blocking surface contacts the secondblocking surface and the first cutting guide surface is substantiallyparallel to the second cutting guide surface and is spaced apart at apredetermined distance therefrom.
 12. The cutting guide of claim 1,wherein the substantially circular bore forms a drill guide extendingfrom an anterior surface of the cutting guide to a posterior surface ofthe cutting guide, the drill guide adapted to receive and guide arotating drill bit.
 13. The cutting guide of claim 9, wherein the firstplurality of holes are spaced apart along the first hinge portion, andwherein the second plurality of holes are spaced apart along the secondhinge portion.
 14. The cutting guide of claim 1, wherein the first andsecond arms are positionable such that the first and second cuttingguide surfaces are parallel to one another and define a slottherebetween having a width substantially corresponding to the thicknessof a saw blade.
 15. The cutting guide of claim 14, wherein at least oneof the first and second arms includes a feature that stops rotation ofthe first and second arms towards one another when the first and secondcutting guide surfaces are parallel to one another.
 16. The cuttingguide of claim 1, wherein the first arm has a plurality of first holesspaced apart along at least a portion thereof and a first fixation hole,wherein the second arm has a plurality of second holes spaced apartalong at least a portion thereof and a second fixation hole, wherein thefirst affixation member is a first fixation pin and the secondaffixation member is a second fixation pin, the first and secondfixation pins each being slidably receivable along a longitudinal axisthereof within the respective first and second fixation holes, whereinthe first and second arms are rotatable with respect to each other aboutan axis so as to define a plane of rotation, and wherein the cuttingguide is adapted to be affixed to the bone with the first and secondfixation pins extending transverse to the plane of rotation and into thebone.
 17. The cutting guide of claim 16, further including a hinge pindefining the axis, wherein each of the first and second holes areadapted to receive the hinge pin therein, and wherein the first andsecond arms are adapted to be arranged such that the hinge pin cansimultaneously extend within one of the first holes and one of thesecond holes.
 18. A cutting guide for performing a bone osteotomyprocedure, comprising: a first arm having a first cutting guide surfaceformed therein, the first arm having a plurality of first holes spacedapart along at least a portion thereof, and the first arm including afirst fixation hole; a second arm pivotably connected to the first arm,the second arm having a second cutting guide surface formed therein, thesecond arm having a plurality of second holes spaced apart along atleast a portion thereof, and the second arm including a second fixationhole; a distractor operatively engaged with both the first and secondarms; a first fixation pin adapted to affix the first arm to a bone, thefirst fixation pin being slidably receivable along a longitudinal axisthereof within the first fixation hole; and a second fixation pinadapted to affix the second arm to the bone, the second fixation pinbeing slidably receivable along a longitudinal axis thereof within thesecond fixation hole; wherein the first arm and second arm are rotatablewith respect to each other about an axis so as to define a plane ofrotation, wherein the cutting guide is adapted to be affixed to the bonewith the first and second fixation pins extending transverse to theplane of rotation and into the bone, such that the first cutting guidesurface faces the second cutting guide surface, and wherein actuation ofthe distractor causes the distractor to apply a force on the first armand an oppositely directed force on the second arm to cause rotation ofthe first arm and second arm relative to each other.
 19. The cuttingguide of claim 18, wherein the first and second fixation holes each havea longitudinal axis that is angled relative to the axis of rotation ofthe first and second arms.
 20. The cutting guide of claim 18, furtherincluding a hinge pin defining the axis, wherein each of the first andsecond holes are adapted to receive the hinge pin therein, and whereinthe first and second arms are adapted to be arranged such that the hingepin can simultaneously extend within one of the first holes and one ofthe second holes.
 21. The cutting guide of claim 18, wherein the firstarm has a first rounded groove formed therein and the second arm has asecond rounded groove formed therein, and wherein the first and secondarms are positionable such that the first and second rounded groovestogether define a substantially circular bore.
 22. The cutting guide ofclaim 18, wherein the first and second arms are positionable such thatthe first and second cutting guide surfaces are parallel to one anotherand define a slot therebetween having a width substantiallycorresponding to the thickness of a saw blade.
 23. The cutting guide ofclaim 22, wherein at least one of the first and second arms includes afeature that stops rotation of the first and second arms towards oneanother when the first and second cutting guide surfaces are parallel toone another.
 24. The cutting guide of claim 18, wherein the bone is theproximal tibia, wherein the cutting guide is adapted to be affixed tothe anterior portion of the proximal tibia, and wherein the first andsecond cutting guide surfaces each include a portion thereof whichextends in an anterior-posterior direction along a side cortex of theproximal tibia.